1. Technical Field
This invention relates to a multicomponent separation/purification process and apparatus for separating the multicomponent mixture containing at least 3 components and purifying each component to be recovered.
2. Related Techniques
Heretofore, techniques such as gas chromatography and liquid chromatography utilizing the difference in distribution coefficient against adsorbents have been known as means for separating and purifying a multicomponent mixture.
These separation/purification means have excellent separation ability and therefore they have been widely used in chemical analysis of complex mixtures. However, when these means are used as separation/purification means on an industrial scale, the purification cost is high due to batch operation. Accordingly, the application fields of such means are limited.
On the other hand, in a pseudo-moving bed adsorption separation apparatus wherein continuous operation is used on an industrial scale such as continuous separation apparatus described in U.S. Pat. No. 2,985,589, a mixture containing 2 components is separated. However, it is difficult to continuously separate a mixture containing at least 3 components by a single apparatus.
In a process for continuously separating 3 components by a pseudo-moving bed adsorption separation apparatus recently proposed in Japanese Patent Laid-Open Publication No. 80409/1989, the separation has been realized by alternately disposing a column packed with a first packing wherein its distribution coefficient against Components A, B and C is Component A&lt;Component B&lt;Component C and a column packed with a second packing wherein its distribution coefficient is Component A&lt;Component C&lt;Component B and flowing the solution through the columns.
However, it is necessary to use mixtures and packing which meet the above condition for the distribution coefficient in such a separation process. Mixtures and packings which meet such requirements are less and therefore ternary or higher mixtures capable of separating and purifying them are limited. Thus, such a process is a less practical separation process.
Further, if multicomponent mixtures containing at least 4 components are separated and purified utilizing the process described above, the conditions become more severe and it is virtually impossible to continuously separate and purify multicomponent mixtures containing at least 4 components.
Furthermore, the process described above discloses only the use of the flow of between-columns and the operation of respective one column and therefore the reflux efficiency is inferior. A long period of time is required until stabilization is obtained or high concentration and high purity are achieved. Since the separated products which is discharged up to the time are in vain or adverse effects such as the reduction of an average purity occur, such facts lead to the increase of production cost and it is difficult to apply such a process to small-quantity production.
In order to get high purity in such a process, mixtures and adsorbents having large difference in distribution coefficient are required, but it is extremely difficult to find such mixtures and adsorbents and therefore subject materials are limited.